Abstract: Legal advice provided in the course of litigation often concerns the selection of information to present to a tribunal. Professors Kaplow and Shavell examine the effects and social desirability of this kind of advice. They observe that such advice may result in either more or less information reaching the tribunal and that, in either case, it will tend to produce more favorable outcomes for clients. Because individuals will take this effect into account when deciding how to act, the prospect of advice may alter their behavior. The authors explore the factors determining whether the influence on behavior is desirable or detrimental. They emphasize that legal advice supplied during litigation differs significantly from advice given when acts are initially contemplated, because only the latter type of advice generally tends to channel behavior in a socially desirable manner. The authors' analysis raises basic questions about the wisdom of the attorney-client privilege and rules protecting confidentiality in the context of litigation, and it suggests that inquiry into the lawyer's role be recast.